A valve element of said type which is in the form of a valve sleeve is known from DE-10 2007 058 491 A1. This valve element is a constituent part of a control valve for the variable adjustment of the timing of gas exchange valves of a reciprocating-piston internal combustion engine. The valve element is screwed into a camshaft which is of hollow form at the end, and said valve element, in conjunction with the control pistons, controls the pressure medium inlet, the control lines that lead to a camshaft adjustment unit, and the pressure medium outlet that is connected by the opening in the spring support to a pressure medium line.
It is a problem that dirt particles can ingress into the control device or valve unit and can impede or block the movement of the valve piston in the valve sleeve.
It is a further problem that pressure medium can flow back out of the control device or valve unit in an undesired manner, and that an evacuation of the lines and of the adjustment chambers in the camshaft adjuster causes an undesired adjustment of the camshaft adjuster of the internal combustion engine or some other adjustment of a transmission.